The invention relates to a vehicle network of two vehicles working in a coordinated manner, such as a harvesting machine and a hauling vehicle that receives crop from the harvesting machine and a device and a method for the coordination thereof.
Harvesting machines in the form of forage harvesters are typically not designed to store notable quantities of crop on board. Instead, the crop to be chopped is continuously transferred to a hauling vehicle traveling adjacent thereto. Although harvesting machines in the form of combine harvesters usually comprise installed crop storage devices and therefore do not need to be continuously accompanied by a hauling vehicle during a harvesting operation, it is desirable in this case as well to be able to transfer the contents of the crop storage device to a hauling vehicle during travel, in order to avoid interrupting the harvesting procedure for the time required for the transfer.
In both cases, the position of the two vehicles relative to one another must be controlled exactly during the transfer procedure in order to ensure that all the transferred crop reaches a loading chamber of the hauling vehicle. Also, it should be possible to vary this position in a controlled manner such that the crop is distributed uniformly in the loading chamber, thereby ensuring good utilization of the capacity of the hauling vehicle.
A device known from EP 2 020 174 B1 for coordinating two vehicles uses a camera in order to identify, in images of the loading chamber, reference points for the positioning of the vehicles relative to one another, namely the edges of a loading chamber, and to detect the height profile of the crop in the loading chamber. On the basis of this height profile, a decision is made whether the position of the two vehicles relative to one another should be changed.
In order to change the impact point of the transferred crop in the hauling vehicle, it is possible with the conventional device to change the position of the transfer device on the harvesting machine. The transfer device is an upper discharge chute, which can swivel about two axes and comprises a swivellable flap mounted on the end thereof. Although it is possible to calculate a position of the transfer device, in the various degrees of freedom thereof, that is required for a desired displacement of the impact point and to control actuators accordingly, deviations occur nevertheless between a desired displacement and an actual displacement due, inter alia, to play in the bearings of the upper discharge chute and play between the upper discharge chute and the actuators driving this upper discharge chute.
Another way to change the impact point is to temporarily drive the two vehicles at different ground speeds. This results in the problem, however, that the vehicles need time to make adjustments in ground speed to adapt to a change in the target ground speed, thereby making it difficult to predict the movement of the vehicles relative to one another and to predict a resultant displacement of the impact point of the crop on the second vehicle during a change in ground speed. In addition, it is difficult to exactly predict and adjust the change in drive power required for a desired change in ground speed. Although it is possible, in a closed control loop, to measure a change in ground speed resulting from a change in drive power and to subsequently correct the drive power if necessary, this requires a considerable amount of time. Therefore, it is difficult to control a rapid and simultaneously accurate displacement of the impact point by means of a change in the vehicle ground speed.